Unfortunately, that tool only gives me all of the data I put on there myself. So nothing I didn’t already have
I believe that is all you are entitled to, under the data portability portion of GDPR:
The data subject shall have the right to receive the personal data concerning him or her, which he or she has provided to a controller
For information about you, uploaded by someone else, I thought your rights are not so clear:
Where personal data have not been obtained from the data subject, the controller shall provide the data subject with the following information:
(c) the purposes of the processing for which the personal data are intended as well as the legal basis for the processing;
(d) the categories of personal data concerned;
(e) the recipients or categories of recipients of the personal data